JP2005158910A - Color mixing device for multicolor light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color mixing device for multicolor light emitting devices in which color mixing performance of light from a plurality of light emitting devices is enhanced through a small and simple arrangement. <P>SOLUTION: The multicolor light emitting device color mixing device 10 comprises a plurality of light emitting devices 12, 13 and 14 emitting light of different colors, and a triangular prism 15 for leading the outgoing light from each light emitting device to one outgoing axis. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a multicolor light emitting element color mixing apparatus in which light emitted from light emitting elements such as a plurality of light emitting diodes and laser elements having different emission colors is mixed and emitted.

Conventionally, such a multicolor light emitting device color mixing apparatus is configured as shown in FIG. 8, for example.
In FIG. 8, the multicolor light emitting element color mixing device 1 is configured as a so-called multicolor LED, and includes three light emitting diode (hereinafter referred to as LED) chips 3 mounted on the bottom surface of the recessed portion 2 a of the substrate 2 by die bonding. , 4, 5 and a resin mold part 6 made of epoxy resin or the like filled in the recessed part 2a of the substrate 2.

  The LED chips 3, 4, 5 are electrically connected to the cathode electrodes 3a, 4a, 5a by wire bonding (not shown), and the LED mounting portion on the upper surface of the substrate 2 is provided. It is connected to the anode electrode 2b or integrally formed.

  Further, the LED chips 3, 4, and 5 are configured in, for example, an AlGaInP system, a GaInN system, and a GaInN system so as to emit different emission colors, such as red, green, and blue, respectively.

According to the multi-color light emitting element color mixing device 1 having such a configuration, a driving voltage is applied to the LED chips 3, 4, and 5 via the electrodes 3 a, 4 a, and 5 a, thereby red light and green light, respectively. Emits light and blue light.
The light from each LED chip 3, 4, 5 is radiated to the outside as mixed color light by being mixed with each other in the resin mold 6 and after being emitted to the outside from the resin mold 6. It has become.

  However, in the multi-color light emitting device color mixing device 1 having such a configuration, the light emission direction from each LED chip 3, 4, 5 is uniquely determined by the resin mold portion 6 and each LED chip 3. , 4 and 5 are difficult to make the mutual interval below a predetermined value. Therefore, the color mixing property of the light from each LED chip 3, 4, 5 is impaired.

On the other hand, in order to improve the color mixing property, a diffusing material such as silica may be mixed in the resin mold portion 6. Thereby, the light from each LED chip 3, 4, 5 is diffused by the diffusing material to improve the mutual color mixing.
However, the scattering of light by such a diffusing material approximates the directivity of the Lambertian distribution, and the output decreases.

There is also a method for realizing color mixing by introducing light from each of the LED chips 3, 4 and 5 into the optical fiber.
However, in such a method, there is a coupling loss between the LEDs 3, 4, 5 and the optical fiber, the size of the apparatus is increased, and the length of the optical fiber is limited. Is not available.

  Furthermore, a method of condensing the light from each LED chip 3, 4, and 5 with a lens and mixing them with each other can be considered, but the lens diameter and lens position must be changed according to the required focal position. In addition, the apparatus becomes large.

  Such a color mixing problem is not limited to the case of LED chips, but also exists in other forms of LED elements, and also in light emitting elements such as laser diodes.

  In view of the above, an object of the present invention is to provide a multicolor light emitting element color mixing device that improves the color mixing characteristics of light from a plurality of light emitting elements with a simple and small configuration.

  According to the present invention, the above object includes a plurality of light emitting elements having different emission colors, and an optical member that guides light emitted from each light emitting element to one output axis. This is achieved by a color light emitting device color mixing device.

  In the multicolor light emitting device color mixing device according to the present invention, preferably, the optical member is a triangular prism, and the light from each light emitting device spaced from each other is changed based on the difference in refraction angle depending on the wavelength of the emitted light. , It is led to one output axis.

  In the multicolor light emitting device color mixing device according to the present invention, preferably, the optical member is a composite prism provided with a reflecting surface that totally reflects light from each light emitting device, and the light from each light emitting device is The light is reflected by the corresponding reflecting surface and guided to one output axis.

  In the multicolor light emitting device color mixing device according to the present invention, preferably, the composite prism has a plurality of parallel arrangements arranged side by side with respect to the output axis so as to have an inner surface that totally reflects light from each light emitting device. It is a quadrilateral prism.

  In the multicolor light emitting device color mixing device according to the present invention, preferably, the optical member is a dichroic prism, and transmits or reflects light from each light emitting device to guide it to one emission axis. .

  In the multicolor light emitting device color mixing device according to the present invention, preferably, the optical member is a diffraction grating, and the light from each of the light emitting devices spaced from each other is changed based on the difference in diffraction angle depending on the wavelength of the emitted light. , It is led to one output axis.

  In the multicolor light emitting device color mixing device according to the present invention, preferably, the diffraction grating is a transmission diffraction grating.

  In the multicolor light emitting device color mixing device according to the present invention, preferably, the diffraction grating is a reflective diffraction grating.

  The multicolor light emitting device color mixing device according to the present invention preferably includes an aperture member having an opening in the vicinity of the output axis of the diffraction grating.

  According to the above configuration, since the light from each light emitting element is optically guided to one emission axis by the optical member, the light of the emitted light from each light emitting element even if the respective light emitting elements are separated from each other. The axes can be aligned with each other by the optical members. Therefore, with a simple configuration, it is possible to easily obtain a good color mixing property without scattering light from each light emitting element or introducing it into the optical fiber.

  When the optical member is a triangular prism and the light from each light emitting element spaced from each other is guided to one output axis based on the difference in refraction angle depending on the wavelength of the output light, each light emitting element Based on the difference in refraction angle when light from the triangular prism enters and exits the triangular prism, it exits in alignment with one outgoing axis when exiting from the triangular prism. Thereby, a good color mixing property can be easily obtained.

  The optical member is a composite prism provided with a reflecting surface that totally reflects light from each light emitting element, and the light from each light emitting element is reflected by the corresponding reflecting surface to be provided on one output axis. In the case of guiding, the light from each light emitting element is totally reflected by the corresponding reflecting surface of the composite prism, and is emitted in alignment with one emission axis. Thereby, a good color mixing property can be easily obtained.

  When the composite prism is a plurality of parallelogram prisms arranged side by side with respect to the emission axis so as to have an inner surface that totally reflects light from each light emitting element, The light is totally reflected by the inner surfaces of the corresponding parallelogram prisms, sequentially passes through the parallelogram prisms, and exits in alignment with the exit axis of the last parallelogram prism. Thereby, a good color mixing property can be easily obtained.

  When the optical member is a dichroic prism, and the light from each light emitting element is guided to one output axis by transmitting or reflecting the light from each light emitting element, the light from each light emitting element is transmitted through the dichroic prism, or By being reflected by the reflecting surface of the dichroic prism, it is emitted in alignment with one emission axis of the dichroic prism. Thereby, a good color mixing property can be easily obtained.

  The optical member is a diffraction grating, preferably a transmissive or reflective diffraction grating, and outputs light from each light emitting element spaced from each other based on a difference in diffraction angle depending on the wavelength of the emitted light. In the case of guiding to the axis, the light from each light emitting element is output in alignment with one output axis when exiting from the triangular prism based on the difference in diffraction angle when entering and exiting the triangular prism. Become. Thereby, a good color mixing property can be easily obtained.

  When an aperture member having an opening is provided near the output axis of the diffraction grating, when the light from each light emitting element is diffracted by the diffraction grating, the light deflected from the desired output axis direction is blocked by the aperture member. By doing so, scattered light can be eliminated.

  Thus, according to the present invention, the light from the light emitting elements having different emission colors is guided to one emission axis by the optical member, so that the light emission axes from the respective light emitting elements are optically aligned with each other. Will do. Therefore, a high color mixing property can be easily obtained with a simple and small configuration without diffusing light from each light emitting element or introducing it into the optical fiber.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 7.
The embodiments described below are preferable specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. As long as there is no description of the effect, it is not restricted to these aspects.

FIG. 1 shows a configuration of a first embodiment of a multicolor light emitting device color mixing apparatus according to the present invention.
In FIG. 1, the multicolor light emitting device color mixing device 10 includes three LED chips 12, 13, and 14 arranged in a horizontal direction on a substrate 11, and a horizontal direction with respect to these LED chips 12 to 14. The triangular prism 15 is disposed adjacent to the triangular prism 15.

Each of the LED chips 12, 13, and 14 has a known configuration, and is configured to emit red light, green light, and blue light, respectively. In this case, the LED chips 12 to 14 are arranged in the order of longer wavelengths from the left, as will be described later.
The triangular prism 15 is formed in the shape of an isosceles triangle having a cross section of an apex angle θ, and is disposed so that one side surface is in contact with the surface of the substrate 11 and the longitudinal axis extends perpendicular to the paper surface. ing.
The triangular prism 15 may be transparent to the light source to be used, that is, the light from each of the LED chips 12 to 14, and is made of transparent glass or transparent resin.

  The light emitted from the LED chips 12, 13, and 14 is incident on the left side surface (incident surface) 15 a of the triangular prism 15, and is emitted from the right side surface (exit surface) 15 b of the triangular prism 15. At this time, each light is refracted by the incident surface 15a and the exit surface 15b based on the wavelength thereof, so that the light is aligned with one horizontal exit axis on the exit surface 15b of the triangular prism 15, and the triangular prism 15 It comes out from.

Here, if the height of the exit position of the exit light on the exit surface 15b of the triangular prism 15 is h, the exit light exits the exit surface 15b of the triangular prism 15 at an exit angle of θ / 2.
At this time, if the prism height is L and the refractive index for incident light is nc, the incident position of the light from each LED chip 12, 13, 14 on the incident surface 15a of the triangular prism 15, that is, the horizontal incident position x _c , The vertical incident position y _{c, the} incident angle i _c , and the prism incident angle φ are expressed by the following four formulas (1) to (4).
(Formula 1)
(Formula 2)
(Formula 3)
(Formula 4)
Here, c is the emission color (R, G, B) of each LED chip 12, 13, 14.

Accordingly, the light from each LED chip 12, 13, and 14 is respectively positioned at the incident surface 15a of the triangular prism 15 at positions (x _R , y _R ), (x _G , y _G ), and (x _B , y _B). ), The light of each luminescent color is emitted from the position of the height h at the exit surface 15b of the triangular prism 15 at the exit angle θ / 2 by being incident at the incident angles i _R , i _G and i _B. Will do.
The horizontal positions of the LED chips 12, 13, and 14 are uniquely determined by the incident position (x _c , y _c ) and the incident angle _ic , respectively. At this time, since the refraction angle increases as the wavelength increases, the LED chips 12, 13, and 14 are arranged so as to approach the triangular prism 15 sequentially from the longer wavelength.

The multi-color light emitting element color mixing device 10 according to the embodiment of the present invention is configured as described above, and when the drive voltage is applied to the LED chips 12, 13, 14, the LED chips 12, 13, 14 emits light, and red light, green light and blue light are emitted.
Thus, each light is refracted by being incident on the incident surface 15a of the triangular prism 15 at the incident angle _ic according to the expression (3) at the incident position represented by the expressions (1) and (2). It penetrates the inside and reaches the exit surface 15b.

Each light is incident and refracted from the inside at a height h of the exit surface 15b of the triangular prism 15 at an approximately incident angle φ, and exits along the optical axis extending horizontally from the exit surface 15b. Will do.
Therefore, the light of each color emitted from the LED chips 12, 13, and 14 is refracted based on the wavelength by the triangular prism 15 as an optical member, and is emitted in alignment with one common emission axis. Will be. As a result, the light of each color can be mixed well with each other, so that the color mixing property is improved.

Here, for example, by mixing the light from the LED chips 12, 13, and 14, in the chromaticity diagram shown in FIG. 2, by appropriately controlling the amount of light emitted from the LED chips 12, 13, and 14, each LED chip. It is possible to create mixed color light having an arbitrary chromaticity inside a triangle whose apex is the chromaticity of light from 12, 13, and 14.
That is, assuming that the spectral distribution of each color of red, green, and blue is R (λ), G (λ), and B (λ), respectively, and the sum of the mixed color light is proportional to these, the chromaticity of the mixed color light is The chromaticity coordinates are given by the following equations (5), (6), and (7) where x = X / S and y = Y / S.
(Formula 5)
(Formula 6)
(Formula 7)
Here, P (λ) = R (λ) + G (λ) + B (λ), x (λ), y (λ) and z (λ) are color matching functions, k is a proportional constant, S = X + Y + Z It is.
Therefore, it is possible to realize the internal chromaticity with the chromaticities represented by RGB as vertices by the mixed color light.

  As described above, according to the multicolor light emitting element color mixing device 10 according to the embodiment of the present invention, by using the triangular prism 15 as the optical member, it can be configured in a simple and small size, and can easily improve the color mixing property. Is possible.

FIG. 3 shows a configuration of a second embodiment of the multicolor light emitting device color mixing apparatus according to the present invention.
In FIG. 3, the multi-color light emitting element color mixing device 20 is arranged above three LED chips 22, 23, and 24 arranged side by side on a substrate 21, and above these LED chips 22 to 24. And a composite prism 25.

  Each LED chip 22, 23, 24 has a known configuration and is configured to emit red light, green light, and blue light, respectively. In this embodiment, the LED chips 22 to 24 are not in any order and may be arranged in any order.

The composite prism 25 is composed of three parallelogram prisms 25a, 25b, and 25c disposed on the upper side corresponding to the LED chips 22 to 24, respectively.
Each of the parallelogram prisms 25a, 25b, and 25c has the same shape, and the cross section is formed into a parallelogram having a base angle θ. The base angle θ is perpendicular to the lower LED chips 22 to 24. The light traveling upward is selected so as to be totally reflected by the oblique inner surfaces of the parallelogram prisms 25a, 25b, and 25c, that is, to satisfy the total reflection condition according to the following expression (8). .
(Formula 8)
Here, φ is an incident angle with respect to the inner surfaces of the parallelogram prisms 25a, 25b, and 25c.

In order to further improve the color mixing property, the base angle θ and the incident angle φ are preferably selected to be 45 degrees.
The parallelogram prism 25 only needs to be transparent to the light source used, that is, the light from each of the LED chips 22 to 24, and is made of transparent glass or transparent resin.

Further, in the embodiment according to FIG. 3, a triangular prism 26 having a base angle of 45 degrees is arranged in order to horizontally convert the output axis from the last parallelogram prism 25c.
Here, the inclined surfaces of the parallelogram prisms 25a to 25c and the triangular prism 26 facing each other have the same inclination angle and are positioned parallel to each other.

The horizontal positions of the LED chips 22, 23, and 24 are sequentially changed even if there is a shift due to the inclined optical axis between the parallelogram prisms 25a, 25b, and 25c. Are selected so that the optical axes of the light reflected by the inner surfaces of the corresponding parallelogram prisms 25a, 25b, and 25c coincide.
In the drawing, the light from the LED chips 22 to 24 is reflected by the corresponding parallelogram prisms 25a to 25c and then the optical axes are slightly shifted from each other. The light is easily identified, and is actually arranged so that the optical axes overlap each other.

According to the multi-color light emitting element color mixing device 20 having such a configuration, when a driving voltage is applied to each LED chip 22, 23, 24, each LED chip 22, 23, 24 emits light, respectively. Red light, green light and blue light are emitted.
As a result, each light travels vertically upward, enters perpendicularly from the lower surfaces of the corresponding parallelogram prisms 25a, 25b, and 25c, and reaches the inclined inner surface. Each light is totally reflected at the inner surface and travels horizontally toward the right in FIG.

  At this time, the light L1 reflected from the inner surface of the parallelogram prism 25a from the LED chip 22 is refracted and emitted from the right slope of the parallelogram prism 25a, and then enters the next parallelogram prism 25b. Refract. At this time, since the exit surface of the parallelogram prism 25a and the entrance surface of the parallelogram prism 25b are parallel to each other, the light L1 is converted into a parallelogram prism by refraction at the entrance surface of the parallelogram prism 25b. Within 25b, it proceeds horizontally toward the right.

Here, the light L2 reflected from the inner surface of the parallelogram prism 25b from the LED chip 23 is refracted and emitted on the right slope of the parallelogram prism 25b in a state where the optical axis overlaps the light L1. become.
Similarly, the lights L1 and L2 are refracted by the exit surface of the parallelogram prism 25b and further refracted by the entrance surface of the last parallelogram prism 25c, so that the inside of the parallelogram prism 25c is turned to the right. It will go horizontally.

The light L3 reflected from the inner surface of the parallelogram prism 25c from the LED chip 24 is refracted and emitted from the right slope of the parallelogram prism 25c in a state where the optical axes of the lights L1 and L2 overlap. It will be.
Therefore, the lights L1, L2, and L3 refracted and emitted from the exit surface of the last parallelogram prism 25c are further incident on the inclined surface 26a of the triangular prism 26, refracted, and proceed horizontally. , And exits from the vertical exit surface 26b and proceeds horizontally toward the right.

  In this way, the light of each color emitted from each LED chip 22, 23, 24 is totally reflected by the composite prism 25 as an optical member, so that the light is emitted in alignment with one common emission axis. Will be. As a result, the light of each color can be mixed well with each other, so that the color mixing property is improved.

FIG. 4 shows a configuration of a third embodiment of the multicolor light emitting device color mixing device according to the present invention.
In FIG. 4, the multicolor light emitting element color mixing device 30 includes three LED chips 31, 32, and 33, and a dichroic prism 34 that is arranged so as to transmit or reflect the light from these LED chips 31 to 33. Has been.

  Each LED chip 31, 32, 33 has a known configuration and is configured to emit red light, green light, and blue light, respectively.

  The dichroic prism 34 has a first incident axis extending coaxially to the left side with respect to an output axis extending to the right side in the drawing, and second and third incident axes extending perpendicularly up and down. A first wavelength-selective thin film 34a extending at an angle of 45 degrees downward with respect to the axis and a second wavelength-selective thin film 34b extending at an angle of 45 degrees upward with respect to the output axis are also provided.

Here, the first wavelength selective thin film 34a has an optical characteristic of reflecting only red light and transmitting green light and blue light.
The second wavelength selective thin film 34b has an optical characteristic of reflecting only blue light and transmitting green light and red light.
These wavelength-selective thin films 34a and 34b are composed of multilayer thin films such as titanium oxide, silicon oxide, cerium oxide, aluminum oxide, and magnesium fluoride, and the film thickness of each thin film has desired optical characteristics. Is selected.

  On the other hand, the LED chips 31, 32, and 33 are disposed on the second optical axis, the first optical axis, and the third optical axis below, to the left, and above the dichroic prism 34, respectively. Yes.

According to the multi-color light emitting element color mixing device 30 having such a configuration, when a driving voltage is applied to the LED chips 31, 32, 33, the LED chips 31, 32, 33 emit light, respectively. Red light, green light and blue light are emitted.
Thereby, the red light from the LED chip 31 enters from below the dichroic prism 34, is reflected by the first wavelength selective thin film 34a, and is guided to the right emission axis. At that time, since the red light is transmitted through the second wavelength selective thin film 34b, only the reflection by the first wavelength selective thin film 34a is effective.

The green light from the LED chip 32 enters from the left side of the dichroic prism 34, passes through the first wavelength-selective thin film 34a and the second wavelength-selective thin film 34b, and enters the right emission axis. Will be guided.
Furthermore, the blue light from the LED chip 33 enters from above the dichroic prism 34, is reflected by the second wavelength selective thin film 34b, and is guided to the right emission axis. At that time, since the blue light is transmitted through the first wavelength selective thin film 34a, only the reflection by the second wavelength selective thin film 34b is effective.

  In this way, light from each of the LED chips 31 to 33 is guided to the right exit axis of the dichroic prism 34, and is emitted in alignment with one common exit axis. . As a result, the light of each color can be mixed well with each other, so that the color mixing property is improved.

FIG. 5 shows the configuration of the fourth embodiment of the multicolor light emitting device color mixing apparatus according to the present invention.
In FIG. 5, the multicolor light emitting device color mixing device 40 includes three LED chips 41, 42, 43, a diffraction grating 44 disposed adjacent to these LED chips 41 to 43, an aperture member 45, It is composed of

Each LED chip 41, 42, 43 has a known configuration and is configured to emit red light, green light, and blue light, respectively. In this case, as will be described later, the LED chips 41 to 43 are arranged in ascending order of wavelength from above.
The diffraction grating 44 is a reflection type diffraction grating having a grating interval D1, and is made of, for example, a metal grating such as aluminum or a vapor deposition film.
Here, when light having a wavelength λ is incident on the diffraction grating 44 at an incident angle γ1, if m is an integer, the first-order diffracted reflected light is emitted in the direction of the emission angle γ2 given by Equation (9). It will be.
(Formula 9)
Therefore, by appropriately setting the grating interval D1 based on the wavelength of the light from each LED chip 41 to 43 and the incident angle γ1 with respect to the diffraction grating 44, the emission angle γ2 with respect to the light of each wavelength is made the same. Can be.
The second-order or lower-order diffracted light is blocked by the aperture member 45 so that it is not emitted in the direction of the emission angle γ2.

  The LED chips 41 to 43 are incident so that the emitted light is incident on the same position of the diffraction grating 44 at different incident angles γ1, and the diffracted reflected light is emitted at the same outgoing angle γ2. The angle γ1 is selected. At that time, the positions of the LED chips 41 to 43 are uniquely determined by the incident angle γ1 given by the equation (9), and the incident angle γ1 is larger as the wavelength is longer. As shown in FIG. 4, the LED chips 41 to 43 are arranged in order from the longest wavelength from the top to the bottom.

According to the multi-color light emitting element color mixing device 40 having such a configuration, when a driving voltage is applied to the LED chips 41, 42, 43, the LED chips 41, 42, 43 emit light, respectively. Red light, green light and blue light are emitted.
Thereby, each light is incident on the same position of the diffraction grating 44 at different incident angles γ1.

Then, each light is emitted as diffraction reflected light at the diffraction grating 44 at the same emission angle γ2 determined by the equation (9) based on the incident angle γ1, the wavelength, and the grating interval D1.
Therefore, the light of each color emitted from each LED chip 41, 42, 43 is diffracted and reflected based on the wavelength by the diffraction grating 44 as an optical member, so that it is aligned with one common emission axis, It will be emitted. As a result, the light of each color can be mixed well with each other, so that the color mixing property is improved.

FIG. 6 shows the configuration of the fifth embodiment of the multicolor light emitting device color mixing apparatus according to the present invention.
In FIG. 6, the multicolor light emitting device color mixing device 50 includes three LED chips 51, 52, and 53, a diffraction grating 54 disposed adjacent to these LED chips 51 to 53, an aperture member 55, It is composed of

Each LED chip 51, 52, 53 has a known configuration and is configured to emit red light, green light, and blue light, respectively. In this case, as will be described later, the LED chips 51 to 53 are arranged in the order of longer wavelengths from above.
The diffraction grating 54 is a transmission type diffraction grating having a grating interval D2, and is made of a metal grating such as aluminum or a vapor deposition film formed on the surface of the transparent material (refractive index n1) on the light incident side.

Here, when light having a wavelength λ is incident on the diffraction grating 54 at an incident angle θ1, assuming that the refractive index of the atmosphere is n2 and m is an integer, the light is emitted in the direction of the emission angle θ2 given by equation (10). Diffracted and transmitted light is emitted.
(Formula 10)
Accordingly, by appropriately setting the grating interval D2 based on the wavelength of the light from each LED chip 51 to 53 and the incident angle θ1 with respect to the diffraction grating 54, the emission angle θ2 of the diffracted transmitted light with respect to the light of each wavelength is set. Can be the same.
In this case as well, second-order or lower-order diffracted light is blocked by the aperture member 55 so that it is not emitted in the direction of the emission angle γ2.

  The LED chips 51 to 53 are incident so that the emitted light is incident on the same position of the diffraction grating 54 at different incident angles θ1 and the diffracted transmitted light is emitted at the same outgoing angle θ2. The angle θ1 is selected.

According to the multi-color light emitting element color mixing device 50 having such a configuration, when a driving voltage is applied to each LED chip 51, 52, 53, each LED chip 51, 52, 53 emits light, respectively. Red light, green light and blue light are emitted.
Thereby, each light enters the same position of the diffraction grating 54 at different incident angles θ1.

Then, each light is emitted as diffraction transmission light at the diffraction grating 54 at the same emission angle θ2 determined by the equation (10) based on the incident angle θ1, the wavelength, and the grating interval D2.
Therefore, the light of each color emitted from each LED chip 51, 52, 53 is diffracted and transmitted based on the wavelength by the diffraction grating 54 as an optical member, and is aligned with one common emission axis and emitted. Will be. As a result, the light of each color can be mixed well with each other, so that the color mixing property is improved.

In the multi-color light emitting element color mixing devices 10 to 50 according to the above-described embodiments, the case where mixed color light is generated by mixing three colors of red light, green light, and blue light from three LED chips has been described. You may make it obtain mixed-color light by the mixture of the light of a color or four colors or more.
For example, in the case of mixed color light by mixing two colors, for example, when two LED chips that emit orange light having a so-called dominant wavelength of about 575 nm and blue light having a wavelength of 470 nm are used, the chromaticity of each LED chip is 7 are positions indicated by both ends A and B of the straight line in the chromaticity diagram of FIG.
Accordingly, assuming that the spectral distribution of each color is A (λ) and B (λ), respectively, and the total sum of the mixed-color light is proportional to these, the chromaticity of the mixed-color light is expressed as chromaticity coordinates x = X / S, y = Y / S is given by the following equations (11), (12) and (13).
(Formula 11)
(Formula 12)
(Formula 13)
Here, P (λ) = A (λ) + B (λ), x (λ), y (λ) and z (λ) are color matching functions, k is a proportional constant, and S = X + Y + Z.
Accordingly, it is possible to realize the chromaticity on the straight line AB by the mixed color light.

In the above-described embodiment, the triangular prism 15, the composite prism 25, the dichroic prism 34, and the diffraction gratings 44 and 54 are used as optical members for guiding the light from each LED chip to one output axis. Not limited to this, an optical member having any other configuration, such as a polarizing element, can be used as long as light from each LED chip can be guided to one output axis.
In the above-described embodiment, the case where an LED chip is used as a light emitting element has been described. However, the present invention is not limited thereto, and various LEDs such as a mold type LED and various light emitting elements including a laser element are used as a light source. It is clear that it is good.

In this way, according to the present invention, it is possible to obtain a good color mixing property that has been difficult with the conventional resin mold LED, and by using an optical member such as a prism or a diffraction grating, a simple and small size can be obtained. With the configuration, it is possible to mix light from each LED chip well.
Therefore, the multicolor light emitting device color mixing apparatus according to the present invention can be used as any light source that requires high color mixing, such as various indicators, light sources for scanners, table light sources, various spotlights, stage lighting, or light sources for temperature sensors. Can do.

It is the schematic which shows the structure of 1st embodiment of the multi-color light emitting element color mixing apparatus by this invention. FIG. 2 is a chromaticity diagram showing a color mixture of emitted light from each LED chip by the multicolor light emitting device color mixing device of FIG. 1. It is the schematic which shows the structure of 2nd embodiment of the multi-color light emitting element color mixing apparatus by this invention. It is the schematic which shows the structure of 3rd embodiment of the multi-color light emitting element color mixing apparatus by this invention. It is the schematic which shows the structure of 4th embodiment of the multi-color light emitting element color mixing apparatus by this invention. It is the schematic which shows the structure of 5th embodiment of the multi-color light emitting element color mixing apparatus by this invention. It is a chromaticity diagram showing color mixing by two-color LED chips. It is (A) schematic plan view and (B) schematic side view which show the structure of the conventional multicolor LED.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Multicolor light emitting element color mixing apparatus 11 Board | substrate 12, 13, 14 LED chip 15 Triangular prism (optical member)
15a entrance surface 15b exit surface 20 multicolor light emitting device color mixing device 21 substrate 22, 23, 24 LED chip 25 compound prism (optical member)
25a, 25b, 25c Parallelogram prism 26 Triangular prism 30 Multicolor light emitting device color mixing device 31, 32, 33 LED chip 34 Dichroic prism (optical member)
34a, 34b Wavelength selective thin film 40 Multicolor light emitting device color mixing device 41, 42, 43 LED chip 44 Reflective diffraction grating (optical member)
50 Multicolor light emitting device color mixing device 51, 52, 53 LED chip 54 Transmission diffraction grating (optical member)

Claims (9)

A plurality of light emitting elements having different emission colors;
An optical member that guides outgoing light from each light emitting element to one outgoing axis;
A multicolor light-emitting element color mixing device comprising: The optical member is a triangular prism,
2. The multicolor light emitting element color mixing device according to claim 1, wherein the light from each of the light emitting elements spaced apart from each other is guided to one output axis based on a difference in refraction angle depending on the wavelength of the output light. . The optical member is a composite prism having a reflecting surface that totally reflects light from each light emitting element,
2. The multicolor light emitting element color mixing device according to claim 1, wherein light from each light emitting element is reflected by a corresponding reflecting surface and guided to one emission axis. 3.   The composite prism is a plurality of parallelogram prisms arranged side by side with respect to the output axis so as to have an inner surface that totally reflects light from each light emitting element. A multicolor light emitting device color mixing device according to claim 1. The optical member is a dichroic prism,
The multicolor light emitting element color mixing device according to claim 1, wherein light from each light emitting element is guided to one output axis by transmitting or reflecting. The optical member is a diffraction grating,
2. The multicolor light emitting element color mixing device according to claim 1, wherein light from each of the light emitting elements spaced apart from each other is guided to one output axis based on a difference in diffraction angle depending on a wavelength of the output light. .   7. The multicolor light emitting element color mixing device according to claim 6, wherein the diffraction grating is a transmission type diffraction grating.   The multicolor light emitting device color mixing device according to claim 6, wherein the diffraction grating is a reflection type diffraction grating.   The multicolor light emitting device color mixing device according to any one of claims 6 to 8, further comprising an aperture member having an opening in the vicinity of an emission axis of the diffraction grating.

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